Purpose:
To assess long-range outcomes of photorefractive keratectomy (PRK) using functionnal and topographic criteria in myopic eyes with suspected keratoconus. Long-term (mean : 4.7 year) follow-up retrospective, interventional case series.
Methods:
The study included 62 eyes of 42 patients classified as keratoconus supects (KCS) or keratoconus (KC) by the corneal navigator of the OPD-Scan II (Nidek, Gamagori, Japan). These patients have been treated with myopic PRK between 2004 and 2007 at the Rothschild Foundation, Paris, France, using the Nidek EC5000 excimer laser. The main outcome measures were refractive stability, mean corneal keratometry, mean central pachymetry, mean thinnest point value, and the occurence of postoperative complications as corneal ectasia.
Results:
Patient population at baseline consisted of 62 eyes of 42 patients. The mean age was 34.6 year +/- 15.1, and the mean spherical equivalent (SE) -3.96 ± 3.05 D (mean sphere -3.48 ± 3.14 D, mean cylinder -0.97 ± 0.92 D. The mean central pachymetry was 529.4 ± 32.8 μm (mean thinnest point 522.1 ± 33.6 μm) and the mean simulated keratometry 45.75 D ± 1.75 D. The percentage of similarity to Keratoconus suspect (KCS) or keratoconus (KC) was positive in all 62 eyes and exceeded a 50% similarity score in 30 eyes (48.4 %). Mean follow-up was 4.8 ± 1.4 years. The mean magnitude of the SE was -0.53 ± 1.35 diopters over the follow-up period, with a mean postoperative keratometry of 42.9 D ± 2.4 D. Only 2 patients had to wear glasses again because of significant myopic regression. No case of corneal ectasia has been reported over the study period.
Conclusions:
Photorefractive keratectomy in eyes with suspected keratoconus based on Placido Neural Network was safe and effective for myopia and astigmatism in carefully selected patients.
Keywords: refractive surgery: PRK • keratoconus • refractive surgery: corneal topography